<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin:0px;
        }
        div{
            width:120px;
            height:120px;
            background-color: red;
            margin:10px;
        }
        p{
            width:30px;
            height:30px;
            background-color: blue;
            margin:5px;
        }
        div:first-child{
            background-color: green;
        }
        p:last-child{
            background-color: green;
        }
        a:link{
            color:blue;
        }
        a:visited{
            color:purple;
        }
        a:hover{
            color:red;
            cursor:pointer
        }
        a:active{
            color:orange;
        }
        #text{
            color: blue;
        }
        div#text::first-letter{
            color: pink;
        }
        div#text::first-line{
            color: pink;
        }
    </style>
</head>
<body>
    <div id="text">
        hello<br>
        world
    </div>
    <a href="#one">百度一下</a>
    <div>
        <p></p>
    </div>
    <div>
        <p></p>
        <p></p>
    </div>
    <div>
    </div>
    <div id="one">
        <p></p>
        <p></p>
        <p></p>
    </div>
</body>
</html>